Not Applicable.
The present invention relates to structural connections for offshore platforms and, more particularly, is concerned with a high capacity nonconcentric structural connector for floating drilling and production platforms that are used in the exploration and production of offshore oil and gas.
An object of this invention is to provide a high capacity structural connection between a dependent space frame attached to a damper plate and a vessel hull. The structural connection must be suitable for reliable, long term service in an open ocean marine environment. An additional objects of this invention is to provide a high capacity, rigid structural connection that can accommodate a substantial axial offset between the two sides of the connection. A further object of this invention is to provide a high capacity structural connection that can be completely assembled or disassembled repeatably by a few workers within a short time. An additional object of this invention is to provide a mounting pattern of structural connections which has high strength and high stiffness in three orthogonal directions when the individual structural connections have high strength and high stiffness in only two orthogonal directions. The connection of the space frame supporting the damper consists of a plurality of individual connectors. Each of the individual connectors has two portionsxe2x80x94one the space frame and the other on the hull.
According to one aspect of the invention, a connector is provided for removably attaching a space frame to the hull of a floating offshore platform. The connector comprises a socket attached to the hull of the platform. The socket has an open bore therein. A stabbing member is attached to the space frame. The stabbing member has a lower end insertable into the socket. An expandable locking ring is carried by the lower end of the stabbing member. The locking ring comprises a plurality of ring segments for removably seating within the socket bore. A backup ring is slidable along the stabbing member. The backup ring removably mates to the locking ring.
According to a second aspect of the invention, a connector is provided for removably attaching a space frame to the hull of a floating offshore platform. The connector comprises a socket attached to the hull of the platform. The socket has an open bore therein. A floor is in the open bore. A latching groove is formed in the socket bore. A stabbing member is attached to the space frame. The stabbing member has a lower end insertable into the socket and an upset head at its lower end. The upset head is removably seatable on the socket floor. The lower end of the stabbing member carries an expandable locking ring. The locking ring comprises a plurality of ring segments for removably seating within the latching groove in the socket bore. The locking ring has a tapered bore therein. A backup ring is downwardly slidable along the stabbing member. The backup ring has a tapered outer surface for removably mating to the tapered bore of the locking ring. A plurality of slip wedges are removably seatable within the socket bore and against the stabbing member. Means is provided for lowering the backup ring from a raised position above the socket to a lowered position seated within the socket.
According to a third aspect of the invention, a method is provided for connecting a space frame to the hull of a floating offshore platform. The method comprises inserting the lower end of a stabbing member attached to the space frame into a socket attached to the hull of the platform. The stabbing member carries an expandable locking ring thereon. The method further comprises lowering a backup ring into mating engagement with the locking ring so as to expand segments of the locking ring into engagement with the socket wall. The method further comprises lowering a plurality of slip wedges into engagement with the socket wall and into engagement with the stabbing member for providing lateral restraint to the stabbing member.